A six-year-old boy who collapsed at a farm in Northern Ireland died from heart failure, the family's minister has said.
Harry Starrett was found in the milking parlour at the family farm on the Ballynahonemore Road, outside Armagh city, on Tuesday evening.
In the wake of the incident, the Health and Safety Executive (HSE) investigated whether he was overcome by slurry fumes from a tank adjacent to the building, but no toxic gases were detected.
A post-mortem examination is now understood to have ruled out a farming accident.
Retired Church of Ireland minister Canon John McKegney, who has known the family for years and will preside at Harry's funeral, said the examination had found a heart defect.
"Harry's death was from natural causes," he said. "A farming accident has been ruled out. They think it is something to do with his heart."
Canon McKegney said the findings had provided some comfort for Harry's "devastated" parents, Mark and Alison. "They are a very safety conscious family and the farm is run very professionally," he added.
It is understood Harry ran ahead of his grandfather Robert as they headed to the empty milking parlour to prepare it for the cows. The boy had gone to pull down the milking clusters in preparation for attaching them to the cows.
When Mr Starrett walked into the parlour minutes later his grandson was lying motionless on the ground.
An ambulance arrived at the farm on the Ballynahonemore Road within minutes and Harry was taken to Craigavon Area Hospital, but efforts to revive him ultimately proved in vain.
Harry, a pupil at Lisnadill primary school in Armagh, was the oldest of four children. He had one brother Ben and two sisters Rebecca and Phoebe.
"They are just in shock," said Canon McKegney.
"I was talking to Mark this morning, they didn't get much sleep."
He added: "Harry loved the farm, he absolutely loved the farm, really lived for it. Even yesterday he didn't want to go home for his meal, he wanted to stay with his grandfather and milk the cows."
The tragedy is not the first to strike the Starrett family. Harry's uncle Thomas was killed in a road accident around 15 years ago.
Canon McKegney said: "I buried his uncle Thomas on Christmas Eve, it's tragic because every Christmas they remember Thomas and now when the Royal prince's birth is remembered they will remember Harry.
"You never forget these things but when there's a link to a public event it can actually be more difficult."
The minister said Harry was a "very special" child.
"I retired in June and at that service Harry was there singing his little heart out in the children's choir," he said.
"He was so cheerful, one of those outgoing lovely little boys every parent would dream of having.
"He would go into a room and just talk to people, always with a smile and a laugh. He was joyful - one of those boys if you gave him £1 he would give 50p of it to his brother."
Canon McKegney added: "He was just a little bundle of joy."
Harry Sinclair, President of the Ulster Farmers' Union, said the entire farming community was in a state of shock over the latest farm death.
"Our thoughts go to that family and the whole agriculture community will be thinking of that family," he said.
Stormont minister and Assembly member for the area Danny Kennedy passed his condolences to the Starrett family.
"I was deeply saddened to learn of the tragic death of such a young child," said the Ulster Unionist representative.
"This terrible news will be a real shock to the local farming community.
"Like all in the local community my thoughts and prayers are with them at this time.
"Whilst in the coming days HSE investigations will take place to establish the precise circumstances, it is only proper that the family are given space at this incredibly difficult time."
Democratic Unionist MLA William Irwin said he was shocked by the incident.
"Since hearing of this sad death, I have been remembering the entire family circle in prayer," he said.
"I know the family concerned. A huge tragedy has just visited their hardworking farm. No human words can describe or encapsulate the grief and pain which comes with the loss of a child."
Last night, Stormont Agriculture Minister Michelle O'Neill told the Belfast Telegraph she was "shocked and saddened to learn of the death of this young boy".
The Sinn Fein MLA added: "My thoughts and prayers go to his family and friends at this difficult time."
Sinn Fein Newry Armagh MLA Cathal Boylan said the death was "an absolute tragedy".